The invention relates to an electronic switch, particularly in the form of a transistor.
An electronic switch is known comprising a semiconductor having a particular doping type and an upper surface. A doping zone can be introduced into the upper surface of the semiconductor by diffusion to form a pn-junction when the doping of the doping zone is of a type opposite to the doping type of the semiconductor body. Electronic switches such as transistors and diodes based on semiconductors are known. For example, if a bipolar transistor with common-emitter connection is to be operated in the avalanche breakdown region at high current densities, it is usually more advantageous if the breakdown voltage is not reached between the collector and emitter with open base because of the risk of destruction by the second breakdown, the so-called reverse second breakdown. As in other circuits with electronic switches, a Zener diode with or without a voltage divider can be used for limiting voltage. An external voltage limiting circuit can be connected to the electronic switch of this type or it can be integrated into the semiconductor. External connection entails additional production cost and the circuitry space requirement is increased. Integrating the voltage limiting circuit in the semiconductor of the electronic switch, e.g. by a planar technique, likewise involves a more costly production process for the electronic switch due to the additional components of the limiting circuit.